Process of manufacturing anthraquinone and phthalic anhydride



Patented Feb. 6, 1923.

UNITED STATES PATENT OFFICE.

'max D. GIBBS, O! PENNSGBOVE, NEW JERSEY, ABSIGHOR '10 E. 1. m1 PORT n: NEMOURS & COITAHY, OF WILMINGTON, DELAWARE, A. CORPORATION 01 nmwm l PROCESS OF mUI'AOTUBING ANT HRAQUINONE AND PH'I'HALIC AHHYIOBIDE.

Ho Drawing.

V Heretofore, anthraquinone has been produced by the high temperature, catalytic air.

oxidation of anthracene, the anthra/cene being in a more or less high state of purity; that is, from 70 to 100% anthracene.

can be produced efliciently from anthracene press cake by the oxidat on of ,the anthracene in the press cake; that phthalic anhydride is produced at the same time by the oxidation of the phenanthrene in the press cake; and that the carbazole resent in the press'cake may be recovered y. prior separation before the substances are passed over the catalyst, or, allowing the carbazole to remain, a large pro ortlon thereof sses over the catalyst unc anged and can recovered along with the products of oxidation.

My invention may be illustrated by the following example: V

The anthraoene press cake, which will contain from- 3040% anthracene and 20-30% carbazole, the remainder consist 40 ing of phenanthrene and other dead oils is mixed with an amount of alkali, eithe caustic soda or caustic potash, suflicient to unite with the carbazole to form the sodium or potassium salt of carbazole and leave a small excess of the alkali. This mixture is then passed through a va rizinga paratus in a continuous manner w are it 15' eated to a temperature of about'200, sometimes as high as 300, and a current of air passed 60 over this mixture. The air stream mixes with the vaporized materials, consisting of anthracene, henanthrene, and other products of the ead oils, andthis as stream is p in contact with the cata yet, which I have now discovered that anthraquinone I Application flied November 14, 1921. lerial lio, 514,838.

is held at a temperature of from about 300 to 500, and preferably, at about 400 G. The products of the reaction are then condensed in any suitable condenser.

The best catalyst that I have found for this operation consists of oxides of vanadium, for example, vanadic oxide, although oxides of moly denum or chromium ma be employed for the purpose. In neral may use an catalytic compound 0 a metal of one of tlie fifth, sixth and eighth groups of the periodic system. The sodium or potassium salt of the carbazole in the above examp1e-dbes not vaporize but is removed from the vaporizer and the carbazole recovered by a separate operation. V 1

r The products of the reaction are condensed and consist of phthalic anhydride, aiithraquinone, and some other products. A separation of these valuable products is best performed by washing out t e acids with a solution of an alkali as for example sodium carbonate thereby orming the sodium salt of the acids which go into solution in the water. The anthr uinone, bein insoluble, is removed by fi tration. T e anthraguinone thus removed by filtration may; if

esired, be purified by a further process, preferably 'by sublimation to separate it from any unoxidized -material.

Although the above exam 1e describes the new process in detail, it wil be understood that various changes 1n operating conditions may be resorted to without departing from my invention. Thus instead of air, I may use oxygengas alone or mixed with one or more inert gases, the resulting i \s in either case being referred to as an oxygen-containmg gas.

clam! :0

1. A process of concurrent y producing anthraquinone and phthalir anhydride which comprises vaporizing the anthracene and phenant-hrene components of anthracene press cake and subjecting saidv vapors in contact with gaseous oxygen to the action of an oxidation catal st at a temperature of from about 300to 00 C. p

2. .A process of concurrently producm anthraquinoiie and phthalic anhydri e and phenanthrene components of anthracene and phenanthrene components ofanthracene press cake and subjecting said vapors 1n contact with gaseous oxygen to the action of an oxide of vanadium at a temperature of from about 300 to 500 C.

3. A process of concurrently produc ng anthraquinone and phthahc anhydride which comprises vaporizing the anthracene and phenanthrene com onents of anthracene press cake, mixing sai vapors w th air, and passing the resulting vapor mixture into contact with a catalytic compound of a metal of one of the fifth, sixth, and eighth groups of the periodic system while ma1n taining said catalytic compound at a temperature between 300 and 650 C.

4. A process of concurrently produc ng anthraquinone and phthalic anhydrlde from anthracene press cake which comprises treating the latter with suflicient caustic alkali to convert the carbazole present into a relatively non-volatile salt, heating the thus treated press cake in a current of air to vaporize the constituents of the press cake other than the carhazole salt, and passing the resulting vapor mixture into contact with a catalytic compound of a metal of one of the fifth, sixth, and eighth groups of the periodic system while maintaining said catalytic compound at a temperature between 300 and 650 C.

In testimony whereof I affix myjsignature.

HARRY D. GIBBS.

Cartiflcate of Correction.

It is hereb certified that in Letters Patent No. 1444,068, granted February 6, 1923, upon e applicaLion of Har D. Gibbs, of iennsgrove, New Jersey, for an im rovement in Prooeg es of anufactm-ipg Anthraquinoiie and Phthalic Anhy 'de, an error appears in the printed specification requirin correction as follows: Page 1, line 106, claim 2, strike out the words and p eml-nthrene 00m nents of anthraoene" and insert. instead which comprise; vapofizing the anti-12cm,- and that the said Lemma Patent sh ould be read'with this correction therein that the same may conform to the record of the case Signed and sealed this 27th day-ofi-February, A, D

Acting 0mm,- of Paiont; 

